Half to henby w



UNITED STATES PATENT OFFICE RUDOLF SILBERBERG, OF JERSEY CITY, NEWJERSEY, ASSIGNOR OF ONE- HALF TO HENRY W. HOOPS, JR, OF SAME PLACE.

MO RDANT.

SPECIFICATION forming part of Letters Patent No. 320,821, dated June 23,1885. Application filed May 8, 1885. (No specimens.) Patented in CanadaApril 20, 1885, No. 21,458.

To all whom it may concern.-

Be it known that I, RUDoLE SILBERBERG, a citizen of the United States,residing at J ersey City, in the county of Hudson and State of NewJersey, have invented certain new and useful Improvements in Mordants,of which the following is a specification.

My invention is an improved mordant of a character to deposit chromiumoxide upon cotton and other fabrics in order to adapt the same to bedyed fast-colors by the use of aniline dyes.

In the preparation of my mordant I use 0xalate 'of chromium, which Iprepare in the following manner: I first dissolve sixty-six pounds ofbichromate of potash in ninetythree pints of boiling Water, and add tothe solution fifty-five pints of nitric acid of a strength of 36 Baum. Ithen prepare a second solution of twenty-nine pounds of oxalic acid insixty pints of water, and add sixteen pints of glycerine of a strengthof 28 Baum. The two solutions are added together and boiled until adiluted solution appears of a clear green color, after which thesolution is allowed to stand until nitrate of potash is deposited ascrystals, when the oxalate of chromium will be in solution in the liquorof a strength of to 88 Baum.

In making the mordant I take twenty quarts of the abovementioned liquordiluted with water to 8 Baum, and mix therewith seventeen and a halfquarts of a solution of caustic soda of a strength of 20 Baum, and afterthe two are well mixed I add five quarts of 5 water.

The mordant mixture thus produced eonstitutes a salable preparation.

\Vhen the mordant is to be used for mordanting fabrics, a portionthereof is diluted 0 with double its volume of cold water, and thegoods,after being soaked in boiling water,are soaked in themordant-liquor for ten hours, and then removed, thoroughly washed, anddyed in the ordinary manner.

I do not here claim the mode of making an oxalate of chromium or themode of dyeing aniline colors therewith, as the same constitutes thesubject of separate applications for Letters Patent Nos. 160,074 and160,075.

I claim- A mordant for preparing fabrics for dyeing with aniline dyes,consisting of a mixture of a solution of oxalate of chromium and asolution of caustic soda, substantially as described.

I11 testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

RUDOLF SILBERBERG.

Witnesses:

FRANK J. MATnEws, HENRY W. HOOPS, Jr.

